Total Phenolics and Total Flavonoids, Nitrate Contents and Microbiological Tests in Dry Extract of Bulgarian White Birch Leaves (Betula pendula)

Recently, the interest in nutritional supplements plant based has increased. Plant extracts of the leaves of white birch (Betula Pendula) have shown the health-promoting properties. Leaves of birch (Betula Pendula) were collected during the period 2005-2008, with a view to their use as food additives and in pharmacy. The total phenolic and total flavonoid contents of dry extract of Betula pendula leaves were evaluated using the Folin-Ciocalteu methods and aluminum chloride colorimetric assay. The determination of nitrates in leaves of birch Betula Pendula has performed using HPLC method for nitrates in fruits and vegetables since a method of non-edible plants is not available. Microbiological contaminants were investigated using the International Pharmacopoeia methods. The following microbiological indicators were covered: total aerobic mesophyllic microorganisms (vegetative and spore forms), Coloforms, Esherichia coli, Salmonella species, Staphylococcus aureus, yeasts and moulds. Current ISO standard methods were used. The dried material from the foliage of Betula Pendula has shown a significant amount of phenols and flavonoids, and compliance with regulatory requirements for nitrates and microbiology.